Constipation means a delay in the discharge of dry and hard feces. It is caused either by a delayed passage of the stomach contents through the intestine or a disorder of the evacuation reflex. Possible reasons for the delayed passage through the intestine are dietetic factors, changes in the intestinal walls or a functional or organic disorder of the nervous system. Also, pharmaceuticals may have a constipating effect. A defect in the defecation mechanism is found in disorders of the anal channel, in the case of loss of the rectal dilation reflex or a weakness in the abdominal muscles used to apply abdominal pressure. Patients complain about symptoms such as a sensation of pressure, flatulence, and pains during the discharge of feces.
Constipation is treated with laxatives which on the one hand soften the hard feces and on the other hand prompt defecation.
Laxatives either act as lubricants, fillers or swelling agents, have saline or osmotic properties, or produce an anti-absorptive or secretagogue effect. The substances of the afore-mentioned groups are combined in commercial preparations in many ways.
When used in long-term therapy, almost all laxatives, except for the swelling agents, increasingly cause disorders of the electrolyte metabolism and in particular cause a potassium loss, which in turn increases constipation. The sodium loss can be so high as to cause a secondary hyperaldesteronism. The potassium losses so caused may lead to a reduced intestine motility and may increase constipation. Moreover, hypokalaemias are above all dangerous when used in therapy together with cardiac glycosides. Concomitant calcium losses can promote the occurrence of osteoporosis, especially in women.
The administration of a swelling agent involves the danger that the stomach contents might stick together, from which the danger of an ileus ensues.
Moreover, many laxatives are resorbed, with the result that they can have a large number of systemic side effects.
Hence, there has been a need for an effective agent for treating constipation which does not produce the aforementioned side effects and consequently lends itself for use in problem patients, for instance children, immobile or geriatric patients and women, in particular during pregnancy.